WASHINGTON – Russian President Vladimir Putin called Robert Mueller's investigation "very objective" Tuesday and said he hoped the special counsel's final report would allow the United States and Russia to reboot their diplomatic relationship, which has been strained by the Kremlin's interference in the 2016 election and questions about whether the Trump campaign colluded with Russia.

"However exotic the work of special counsel Mueller was, I have to say that on the whole, he has had a very objective investigation, and he confirmed that there were no traces whatsoever of collusion between Russia and the incumbent administration, which we said was absolutely fake," Putin said before a closed-door meeting with Secretary of State Mike Pompeo in Sochi on Tuesday.

Putin said he believes President Donald Trump "intends to rebuild U.S.-Russian relations," and he hopes "right now the conducive environment is being built for that."

Pompeo pressed Russian Foreign Minister Sergey Lavrov, in an earlier private meeting Tuesday, to prove that Russian meddling in U.S. elections had stopped.

Russian President Vladimir Putin meets with Secretary of State Mike Pompeo at the Bocharov Ruchei residence in Sochi, Russia, on May 14, 2019.

Pompeo said Trump shares the desire to "change the trajectory" of America's fraught relationship with Russia, but it could further deteriorate if Putin's government continues its efforts to undermine American democracy.

The back-and-forth about Russian election interference came during a high-stakes visit by Pompeo to Sochi, a Russian beach resort on the Black Sea, where Pompeo and Lavrov met for a wide-ranging discussion that touched on tensions over Iran, Venezuela and nuclear arms control. Pompeo then met with Putin for nearly two hours.

"We talked about nearly every issue facing our two countries, all the challenges and all the opportunities between us as well," Pompeo told reporters afterwards.

During a joint news conference with Pompeo, Lavrov raised Mueller's investigation unprompted, and said Russian officials hoped the release of the special counsel's report would close an acrimonious chapter in U.S.-Russian relations.

"We hope this tumultuous situation will die down and we can finally move on to building more professional, constructive dialogue between Russia and the U.S.," the Russian diplomat said.

Pompeo said he pressed Lavrov on Russia's interference in the 2016 U.S. presidential election and "conveyed that there are things Russia can do to demonstrate that these types of activities are a thing of the past."

Pompeo did not elaborate on what steps Russia could take, but he said if the Kremlin interferes in the 2020 election, "it would put our relationship in an even worse place than it’s been."

The two men said they had a "frank" discussion about a range of other geopolitical flashpoints:

Iran

Kremlin officials have expressed frustration with the Trump administration's increasingly aggressive rhetoric about the threat Iran poses – and a possible U.S. military response. The Trump administration has made isolating Iran economically and politically the cornerstone of its foreign policy.

Pompeo declined to comment on a New York Times story published Tuesday, which said acting Defense Secretary Patrick Shanahan presented a military plan to send as many as 120,000 U.S. troops to the Middle East in the event of an Iranian strike on U.S. forces or a move by Iran to speed up its development of nuclear weapons.

"We fundamentally do not see a war with Iran," Pompeo said. He said the United States wants Iran to stop funding terrorist groups and to "behave like a normal country."

Lavrov said he hoped the report was "just a rumor" and expressed fears that tensions could spark a military confrontation.

"This region is so tense with different conflicts and different situations," Lavrov said. He said he told Pompeo he hopes they can find a "political solution" to the Iran situation, so it does not "tip over to the military scenario."

Nuclear weapons treaty

Perhaps the most consequential item on the agenda is a landmark U.S.-Russian arms control treaty called New START. Some advocates and lawmakers fear the Trump administration will abandon the treaty and spark a new nuclear arms race.

President Donald Trump and Russian counterpart Vladimir Putin

Trump administration officials said they’re pushing to broaden the U.S. pact to include China, aiming to craft a deal that limits China’s strategic warheads and other weapons.

They argue that China's growing arsenal has changed the dynamics of arms control, and this new era requires a broader approach than the New START treaty offers.

"The president has charged his national security team to think more broadly about arms control to include countries beyond our traditional U.S.-Russia framework and a broader range of weapons systems," Pompeo said Tuesday.

“China does not see any necessity and does not intend to join bilateral talks between Russia and the U.S on nuclear disarmament,” Chinese Foreign Minister Wang Yi said Monday during his own meeting with Russian officials in Sochi. “We keep our nuclear arsenal at a minimum level, the bare necessary level to maintain our defense.”

Critics questioned the Trump administration’s quest for a trilateral agreement, saying it’s a risky gambit that could jeopardize the New START treaty, which limits the United States and Russia to no more than 1,550 deployed strategic warheads, among other restrictions. That agreement lapses in February 2021, and experts said negotiations need to begin immediately if the Trump administration wants to renew New START.

If New START is allowed to lapse, “there will be no legally binding limits on the world’s two largest nuclear arsenals for the first time in nearly five decades,” Daryl Kimball, executive director of the Arms Control Association, a nonpartisan nonproliferation group, wrote in an analysis of the nascent negotiations.

Kimball noted that the U.S. and Russian nuclear arsenals, when combined, comprise more than 90% of the world’s nuclear weapons. He expressed fears that the Trump administration’s position is a ruse to kill the New START treaty, not broaden it, by making unrealistic demands.

Trump’s national security adviser, John Bolton, is an ardent opponent of arms control agreements, Kimball wrote, suggesting “this new grand-deal gambit does not represent a serious attempt to halt and reverse a global arms race."

“It is more likely that Trump and Bolton are scheming to walk away from New START by setting conditions they know to be too difficult to achieve,” he said.